docker inspect supports Go Templates via the --format option. This allows for better integration in scripts, without resorting to pipes/sed/grep traditional tools.
Print a container internal IP:
docker inspect --format '{{ .NetworkSettings.IPAddress }}' 7786807d8084
This is useful for direct ne...
Fortran 2003 introduced intrinsic modules which provide access to special named constants, derived types and module procedures. There are now five standard intrinsic modules:
ISO_C_Binding; supporting C interoperability;
ISO_Fortran_env; detailing the Fortran environment;
IEEE_Exceptions, IEEE_...
INSERT INTO will append to the table or partition, keeping the existing data intact.
INSERT INTO table yourTargetTable SELECT * FROM yourSourceTable;
If a table is partitioned then we can insert into that particular partition in static fashion as shown below.
INSERT INTO TABLE yourTarge...
Given a sequence of steps we use repeatedly, it's often handy to store it in a function. Pipes allow for saving such functions in a readable format by starting a sequence
with a dot as in:
. %>% RHS
As an example, suppose we have factor dates and want to extract the year:
library(magrittr) ...
You should verify every received string as being valid UTF-8 before you try to store it or use it anywhere. PHP's mb_check_encoding() does the trick, but you have to use it consistently. There's really no way around this, as malicious clients can submit data in whatever encoding they want.
$str...
If you need to match characters that are a part of the regular expression syntax you can mark all or part of the pattern as a regex literal.
\Q marks the beginning of the regex literal.
\E marks the end of the regex literal.
// the following throws a PatternSyntaxException because of the un-close...
The following code will print the arguments to the program, and
the code will attempt to convert each argument into a number (to a
long):
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <limits.h>
int main(int argc, char* argv[]) {
for (int ...
Python 2.x2.7
To import a module through a function call, use the importlib module (included in Python starting in version 2.7):
import importlib
random = importlib.import_module("random")
The importlib.import_module() function will also import the submodule of a package directly:
c...
A unique index prevents the insertion of duplicated data in a table. NULL values can be inserted in the columns that form part of the unique index (since, by definition, a NULL value is different from any other value, including another NULL value)
-- Creates a unique index for column 'name' in tabl...
There is a limit to the depth of possible recursion, which depends on the Python implementation. When the limit is reached, a RuntimeError exception is raised:
def cursing(depth):
try:
cursing(depth + 1) # actually, re-cursing
except RuntimeError as RE:
print('I recursed {} times!'....
To share files or to host simple websites(http and javascript) in your local network, you can use Python's builtin SimpleHTTPServer module. Python should be in your Path variable. Go to the folder where your files are and type:
For python 2:
$ python -m SimpleHTTPServer <portnumber>
For p...
Suppose we want to write a factory function that accepts an arbitrary list of arguments and passes those arguments unmodified to another function. An example of such a function is make_unique, which is used to safely construct a new instance of T and return a unique_ptr<T> that owns the instan...
Defining a member block inside a resource creates a route that can act on an individual member of that resource-based route:
resources :posts do
member do
get 'preview'
end
end
This generates the following member route:
get '/posts/:id/preview', to: 'posts#preview'
# preview_post_p...
If you are building a function that may be heavy on the processor (either clientside or serverside) you may want to consider a memoizer which is a cache of previous function executions and their returned values. This allows you to check if the parameters of a function were passed before. Remember, p...
The specifier override has a special meaning in C++11 onwards, if appended at the end of function signature. This signifies that a function is
Overriding the function present in base class &
The Base class function is virtual
There is no run time significance of this specifier as is mainl...
